solid acid alkylation catalyst and preparation method and application thereof

文档序号：1778149 发布日期：2019-12-06 浏览：26次中文

阅读说明：本技术 固体酸烷基化催化剂及其制备方法和应用 (solid acid alkylation catalyst and preparation method and application thereof ) 是由付强慕旭宏李永祥张成喜胡合新于 2018-05-28 设计创作，主要内容包括：本公开涉及一种固体酸烷基化催化剂及其制备方法和应用,以催化剂的干基重量为基准,该催化剂包括以干基重量计38～90重量％的改性Y分子筛、以干基重量计8～60重量％的载体、以及以金属计0.1～2重量％的具有加氢功能的金属助剂；所述改性Y分子筛的骨架SiO2/Al2O3的摩尔比为5.0～6.0,微孔比表面积为400～600m2/g,微孔孔容为0.25～0.35cm3/g,介孔比表面积为30～200m2/g,介孔孔容为0.07～0.85cm3/g,介孔孔径为2.0～6.0nm,以所述改性Y分子筛的总重量为基准,所述改性Y分子筛中氧化钠的含量不超过0.1重量％。本公开的催化剂适合催化异构烷烃与低碳烯烃的烷基化反应,能够有效提高目标产物三甲基戊烷的选择性,同时可限制不需要的C9+副产物的产量,催化剂使用寿命长,稳定性好,经临氢再生后活性可恢复到新鲜剂水平。(the present disclosure relates to a solid acid alkylation catalyst, a preparation method and an application thereof, wherein the catalyst comprises a modified Y molecular sieve in an amount of 38-90 wt% based on the dry weight of the catalyst, a carrier in an amount of 8-60 wt% based on the dry weight of the catalyst, and a metal auxiliary agent with a hydrogenation function in an amount of 0.1-2 wt% based on metal; the modified Y molecular sieve has a framework SiO2/Al2O3 molar ratio of 5.0-6.0, a micropore specific surface area of 400-600 m2/g, a micropore volume of 0.25-0.35 cm3/g, a mesopore specific surface area of 30-200 m2/g, a mesopore volume of 0.07-0.85 cm3/g and a mesopore diameter of 2.0-6.0 nm, and the content of sodium oxide in the modified Y molecular sieve is not more than 0.1 wt% based on the total weight of the modified Y molecular sieve. The catalyst disclosed by the invention is suitable for catalyzing alkylation reaction of isoparaffin and low-carbon olefin, can effectively improve the selectivity of a target product trimethylpentane, can limit the yield of an unnecessary C9+ byproduct, has long service life and good stability, and can restore the activity to the level of a fresh agent after hydroregeneration.)

1. The solid acid alkylation catalyst is characterized by comprising 38-90 wt% of modified Y molecular sieve based on the dry weight of the catalyst, 8-60 wt% of carrier based on the dry weight of the catalyst, and 0.1-2 wt% of metal auxiliary agent with hydrogenation function based on metal;

The modified Y molecular sieve has a framework SiO2/Al2O3 molar ratio of 5.0-6.0, a micropore specific surface area of 400-600 m2/g, a micropore volume of 0.25-0.35 cm3/g, a mesopore specific surface area of 30-200 m2/g, a mesopore volume of 0.07-0.85 cm3/g and a mesopore diameter of 2.0-6.0 nm, and the content of sodium oxide in the modified Y molecular sieve is not more than 0.1 wt% based on the total weight of the modified Y molecular sieve.

2. The catalyst according to claim 1, wherein the catalyst comprises 59-85 wt% of modified Y molecular sieve based on dry weight of the catalyst, 14-40 wt% of carrier based on dry weight of the catalyst, and 0.1-1 wt% of metal promoter with hydrogenation function based on metal.

3. the catalyst of claim 1 or 2, wherein the modified Y molecular sieve is prepared by a process comprising the steps of:

a. mixing sodium metaaluminate with water glass to obtain a first mixture, dynamically aging and standing aging the first mixture, and then mixing the first mixture with water to obtain a second mixture, wherein the second mixture comprises Na2O: A12O3: SiO2: H2O ═ 6 to 25: 1: (6-25): (200-400);

b. Mixing the second mixture obtained in the step a with water, a silicon source and an aluminum source to obtain a third mixture;

c. B, performing hydrothermal crystallization on the third mixture obtained in the step b, and collecting a solid obtained after the hydrothermal crystallization;

d. re-pulping the solid obtained in the step c, mixing the obtained slurry with a silane coupling agent and a quaternary ammonium salt surfactant, and reacting for 4-48 hours at the temperature of 60-200 ℃ and under the autogenous pressure to obtain a NaY molecular sieve;

e. and d, sequentially carrying out ammonium sodium reduction, hydrothermal treatment and dealumination and silicon supplement on the NaY molecular sieve obtained in the step d to obtain the modified Y molecular sieve.

4. the catalyst of claim 3, wherein in step a, the dynamic aging comprises: stirring and aging for 5-48 hours at 15-60 ℃; the standing and aging comprises the following steps: standing and aging for 5-48 hours at 15-60 ℃.

5. The catalyst of claim 3, wherein in step b, the composition of the third mixture, calculated as oxides and in moles, is Na2O: A12O3: SiO2: H2O ═ 2-6: 1: (8-20): (200-400);

The silicon source is at least one selected from water glass, silica sol, silica gel and white carbon black; the aluminum source is at least one selected from sodium metaaluminate, aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum hydroxide and pseudo-boehmite.

6. The catalyst according to claim 3, wherein the aluminum element in the second mixture accounts for 3 to 30% of the aluminum element in the third mixture, on an elemental basis and on a molar basis.

7. The catalyst according to claim 3, wherein in step c, the hydrothermal crystallization conditions are: the temperature is 90-100 ℃, and the time is 15-48 hours.

8. The catalyst according to claim 3, wherein in step d, the molar ratio of the slurry to the silane coupling agent and the quaternary ammonium salt type surfactant, calculated as A12O3, is 1: (0.04-10): (0.04 to 10);

the silane coupling agent is a compound represented by a general formula R1Si (L1)3, L1 is one selected from methoxy, ethoxy, chlorine and methoxyethoxy, R1 is one selected from phenyl, C1-C22 chain alkyl, C1-C22 alkenyl and hydrocarbon with a substituent at the tail end, and in the hydrocarbon with the substituent at the tail end, the substituent is at least one selected from chlorine, amino, epoxy, vinyl and methacryloxy; preferably, the silane coupling agent is at least one selected from the group consisting of octadecyltrimethoxysilane, vinyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane and 3- (2, 3-glycidoxy) propyltrimethoxysilane;

the quaternary ammonium salt surfactant is a compound represented by a general formula R2N (R3)3X, R2 is a chain alkyl group of C8-C22, R3 is a hydrocarbyl group, and X is halogen or hydroxyl; preferably, the quaternary ammonium salt type surfactant is at least one selected from the group consisting of dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

9. The catalyst of claim 3, wherein in step e, the ammonium cross-reduced sodium comprises: treating the NaY molecular sieve by adopting an ammonium salt solution with the ammonium ion concentration of 0.1-1.0 mol/L, wherein the treatment conditions are as follows: the temperature is 50-100 ℃, and the liquid-solid weight ratio is (8-15): 1, the time is 0.5-1.5 hours; the ammonium salt is at least one selected from ammonium nitrate, ammonium sulfate, ammonium chloride and ammonium acetate;

the hydrothermal treatment comprises: treating the NaY molecular sieve subjected to sodium reduction by ammonium exchange for 1-3 hours under the conditions of 100% of water vapor, gauge pressure of 0.1-0.2 MPa and temperature of 500-650 ℃;

The dealuminizing and silicon supplementing method comprises the following steps: pulping the NaY molecular sieve after the hydrothermal treatment to obtain a product with a liquid-solid weight ratio of (3-10): 1, (NH4)2SiF6 is added into the slurry according to the charging amount of 10-60 g (NH4)2SiF6 added into each 100g of NaY molecular sieve, and the mixture is stirred for 0.5-5 hours at the temperature of 80-120 ℃, so that a product is recovered.

10. The catalyst of claim 1, wherein the support comprises a first component comprising alumina, a second component comprising silica, and optionally clay, wherein the weight ratio of the first component, calculated as Al2O3, the second component, calculated as SiO2, and the clay, calculated on a dry basis, is 1: (0.01-1): (0-3);

Preferably, the first component comprises aluminum sol and hydrated alumina, and the weight ratio of the aluminum sol to the hydrated alumina is 1: (0.2-5);

The second component is at least one selected from silica sol, orthosilicate and white carbon black.

11. The catalyst according to claim 1, wherein the metal promoter having a hydrogenation function is at least one selected from group VIII metals;

Preferably, the metal auxiliary agent having a hydrogenation function is at least one selected from rhodium, platinum, palladium, nickel and ruthenium.

12. The catalyst of claim 1, wherein the catalyst has a strength of 8-9.3N/mm.

13. A process for preparing a catalyst according to any one of claims 1 to 12, comprising:

Forming and roasting mixed slurry containing a modified Y molecular sieve, a carrier and an adhesion promoter to obtain a roasted material, and then loading the metal auxiliary agent with the hydrogenation function on the roasted material to obtain the solid acid alkylation catalyst;

Alternatively, the method comprises:

and loading the metal auxiliary agent with the hydrogenation function on the modified Y molecular sieve to obtain a metal-loaded Y molecular sieve, and then molding and roasting mixed slurry containing the metal-loaded Y molecular sieve, a carrier and an adhesion promoter to obtain the solid acid alkylation catalyst.

14. The method of claim 13, wherein the adhesion promoter comprises an acid and water, the acid being at least one selected from hydrochloric acid, nitric acid, and phosphoric acid;

the solid content of the mixed slurry is 35-40 wt%;

The molding is at least one selected from the group consisting of bar extrusion molding, ball rolling molding, and spray molding.

15. Use of a catalyst according to any one of claims 1 to 12 for the alkylation of isoparaffins with lower olefins under alkylation conditions comprising: the temperature is 40-100 ℃, the pressure is 2.0-5.0 MPa, the feeding space velocity is 10-3000 mL/(g.h), and the molar ratio of the isoparaffin to the low-carbon olefin is (20-1000): 1.

Technical Field

The present disclosure relates to a solid acid alkylation catalyst, a preparation method and applications thereof.

Background

In the petroleum refining industry, the alkylation reaction process of isoparaffin and C3-C6 olefin is an important process for producing clean and high-octane gasoline components. The alkylated gasoline has low vapor pressure, low sensitivity, good antiknock performance, no arene and olefin, and low sulfur content, and is one ideal blending component for high octane gasoline.

the alkylation reaction is an acid-catalyzed reaction. The current alkylation production processes applied industrially include sulfuric acid process and hydrofluoric acid process, which are processes of synthesizing alkylate from isoparaffin and olefin by using liquid sulfuric acid or hydrofluoric acid as a catalyst. Because of the corrosivity and toxicity of the liquid acid catalysts sulfuric acid and hydrofluoric acid and the harm of waste acid discharge in the process to the environment, the pressure of safety and environmental protection for alkylate oil production enterprises is increasing day by day.

to address these problems, many major oil companies and scientific research institutes around the world have been working on the research and development of solid acid alkylation process technologies to replace the liquid acid process with an environmentally friendly solid acid process.

The core of the solid acid alkylation process is the development of a solid acid catalyst with excellent performance, and the solid acid alkylation process has the advantages of good stability, no corrosion to equipment, convenience for separation from a product, less environmental pollution, relatively high safety in a transportation process and the like, and is an ideal form of a future catalyst. Solid acid alkylation catalysts are mainly classified into four types: metal halide, solid super acid, supported heteropoly acid and molecular sieve. Although the development of solid acid catalysts for the alkylation of isobutane with butenes has been in progress for decades, the process technology industrialization has been affected due to the rapid deactivation of the developed solid acid catalysts during the alkylation reaction.

patent US5986158 discloses an alkylation method, the catalyst adopted comprises hydrogenation functional components and solid acid components, and is regenerated by saturated hydrocarbon washing and hydrogenation conditions, the reaction process is carried out in a fixed bed reactor, the active period of the catalyst is only less than 4-10 h, the catalyst must be repeatedly regenerated, and the Research Octane Number (RON) of the alkylate oil is 91.2, trimethylpentane/dimethylhexane is 2.9, and the research octane numbers of C5-C7, C8 and C9+ are respectively 30.4%, 58.2% and 11.4%.

patent EP1527035 discloses a continuous alkylation process carried out in a plant comprising at least two series-connected catalyst-containing reactors located in zone a and at least two series-connected catalyst-containing reactors located in zone B; each zone is cycled back and forth between an alkylation mode and a mild regeneration mode, each zone having at least two reactors in series, and the product stream of the alkylate may or may not be subjected to a prior batch separation in which a portion of the alkylate is removed; the catalyst employs a mild regeneration mode comprising contacting the solid acid alkylation catalyst with hydrogen and a portion of the alkylate effluent comprising the alkylation mode in each of at least two reactors in the zone.

Patent EP1392627 discloses a process for the catalytic alkylation of hydrocarbons which comprises (i) reacting an alkylatable compound with an alkylating agent over a solid acid alkylation catalyst to form an alkylate and (ii) regenerating said catalyst under mild regeneration conditions and in the presence of hydrogen and a hydrocarbon, wherein the hydrocarbon comprises at least a portion of the alkylate that has been formed.

Patent EP1286769 discloses a new alkylation catalyst and its use for the alkylation of hydrocarbons.

Patent CN103964994 discloses an alkylation process for the alkylation of isobutane and butene in the presence of a catalyst and under alkylation conditions, wherein the catalyst is prepared by a process comprising a step of modifying a molecular sieve and a step of introducing a matrix.

although these catalysts have certain catalytic performance, there is still a need to further improve the catalytic activity, selectivity and stability of these catalysts, solve the regeneration problem of the catalysts, and realize the repeated regeneration and recycling of the catalysts.

disclosure of Invention

The purpose of the present disclosure is to provide a solid acid alkylation catalyst, a preparation method and an application thereof, which realize high target product selectivity and catalyst regeneration of alkylation reaction.

to achieve the above object, a first aspect of the present disclosure: providing a solid acid alkylation catalyst, wherein the catalyst comprises 38-90 wt% of modified Y molecular sieve based on the dry weight of the catalyst, 8-60 wt% of carrier based on the dry weight of the catalyst, and 0.1-2 wt% of metal auxiliary agent with hydrogenation function based on metal;

optionally, the catalyst comprises 59-85 wt% of modified Y molecular sieve based on the dry weight of the catalyst, 14-40 wt% of carrier based on the dry weight of the catalyst, and 0.1-1 wt% of metal promoter with hydrogenation function based on the metal.

Alternatively, the modified Y molecular sieve is prepared by a method comprising the steps of:

a. Mixing sodium metaaluminate with water glass to obtain a first mixture, dynamically aging and standing aging the first mixture, and then mixing the first mixture with water to obtain a second mixture, wherein the second mixture comprises Na2O: A12O3: SiO2: H2O ═ 6 to 25: 1: (6-25): (200-400);

b. Mixing the second mixture obtained in the step a with water, a silicon source and an aluminum source to obtain a third mixture;

c. B, performing hydrothermal crystallization on the third mixture obtained in the step b, and collecting a solid obtained after the hydrothermal crystallization;

d. Re-pulping the solid obtained in the step c, mixing the obtained slurry with a silane coupling agent and a quaternary ammonium salt surfactant, and reacting for 4-48 hours at the temperature of 60-200 ℃ and under the autogenous pressure to obtain a NaY molecular sieve;

e. And d, sequentially carrying out ammonium sodium reduction, hydrothermal treatment and dealumination and silicon supplement on the NaY molecular sieve obtained in the step d to obtain the modified Y molecular sieve.

Optionally, in step a, the dynamic aging comprises: stirring and aging for 5-48 hours at 15-60 ℃; the standing and aging comprises the following steps: standing and aging for 5-48 hours at 15-60 ℃.

Optionally, in step b, the composition of the third mixture is Na2O: A12O3: SiO2: H2O ═ 2-6: 1: (8-20): (200-400);

optionally, the aluminum element in the second mixture accounts for 3-30% of the aluminum element in the third mixture in terms of elements and moles.

Optionally, in step c, the conditions of the hydrothermal crystallization are as follows: the temperature is 90-100 ℃, and the time is 15-48 hours.

Alternatively, in the step d, the molar ratio of the slurry to the silane coupling agent and the quaternary ammonium salt type surfactant calculated as A12O3 is 1: (0.04-10): (0.04 to 10);

Optionally, in step e, the ammonium-sodium salt comprises: treating the NaY molecular sieve by adopting an ammonium salt solution with the ammonium ion concentration of 0.1-1.0 mol/L, wherein the treatment conditions are as follows: the temperature is 50-100 ℃, and the liquid-solid weight ratio is (8-15): 1, the time is 0.5-1.5 hours; the ammonium salt is at least one selected from ammonium nitrate, ammonium sulfate, ammonium chloride and ammonium acetate;

The hydrothermal treatment comprises: treating the NaY molecular sieve subjected to sodium reduction by ammonium exchange for 1-3 hours under the conditions of 100% of water vapor, gauge pressure of 0.1-0.2 MPa and temperature of 500-650 ℃;

optionally, the carrier comprises a first component comprising alumina, a second component comprising silica and optionally clay, the weight ratio of the first component, calculated as Al2O3, the second component, calculated as SiO2 and the clay, calculated on a dry basis, being 1: (0.01-1): (0-3);

Preferably, the first component comprises aluminum sol and hydrated alumina, and the weight ratio of the aluminum sol to the hydrated alumina is 1: (0.2-5);

the second component is at least one selected from silica sol, orthosilicate and white carbon black.

Optionally, the metal promoter with the hydrogenation function is at least one selected from group VIII metals;

Preferably, the metal auxiliary agent having a hydrogenation function is at least one selected from rhodium, platinum, palladium, nickel and ruthenium.

Optionally, the catalyst has a strength of 8 to 9.3N/mm.

In a second aspect of the present disclosure: there is provided a process for preparing a catalyst according to the first aspect of the present disclosure, the process comprising:

Alternatively, the method comprises:

And loading the metal auxiliary agent with the hydrogenation function on the modified Y molecular sieve to obtain a metal-loaded Y molecular sieve, and then molding and roasting mixed slurry containing the metal-loaded Y molecular sieve, a carrier and an adhesion promoter to obtain the solid acid alkylation catalyst.

optionally, the adhesion promoter comprises an acid and water, the acid being at least one selected from hydrochloric acid, nitric acid and phosphoric acid;

The solid content of the mixed slurry is 35-40 wt%;

the molding is at least one selected from the group consisting of bar extrusion molding, ball rolling molding, and spray molding.

A third aspect of the disclosure: there is provided a use of the catalyst according to the first aspect of the present disclosure in catalyzing an alkylation reaction of isoparaffin with lower olefin, wherein the alkylation reaction conditions include: the temperature is 40-100 ℃, the pressure is 2.0-5.0 MPa, the feeding space velocity is 10-3000 mL/(g.h), and the molar ratio of the isoparaffin to the low-carbon olefin is (20-1000): 1.

Through the technical scheme, the catalyst disclosed by the invention contains the special modified Y molecular sieve with a regular mesoporous-microporous structure, so that the modified Y molecular sieve is favorable for macromolecular diffusion, is particularly suitable for catalyzing alkylation reaction of isoparaffin and low-carbon olefin, can effectively improve the selectivity of a target product trimethylpentane, and can limit the yield of an unnecessary C9+ byproduct. In addition, the catalyst disclosed by the invention has the advantages of high strength, long service life and good stability, and the activity can be restored to the level of a fresh agent after the catalyst is regenerated by hydrogen.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 is an XRD spectrum of a sample of the NaY molecular sieve prepared in example 1;

FIG. 2 is a small angle XRD spectrum of a sample of the NaY molecular sieve prepared in example 1;

FIG. 3 is a BET adsorption-desorption isotherm of a NaY molecular sieve sample prepared in example 1 and a comparative sample prepared in comparative example 1;

FIG. 4 is an SEM image of a sample of the NaY molecular sieve prepared in example 1;

FIG. 5 is an XRD spectrum of a comparative sample prepared in comparative example 1;

FIG. 6 is a small angle XRD spectrum of a comparative sample prepared in comparative example 1;

Fig. 7 is an SEM spectrum of a comparative sample prepared in comparative example 1.

Detailed Description

the following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

The first aspect of the disclosure: the solid acid alkylation catalyst comprises 38-90 wt% of modified Y molecular sieve based on the dry weight of the catalyst, 8-60 wt% of carrier based on the dry weight of the catalyst, and 0.1-2 wt% of metal promoter with hydrogenation function based on metal.

According to the disclosure, the modified Y molecular sieve has a regular meso-microporous structure, and the connectivity between meso pores and micropores is good, which is beneficial to macromolecule diffusion. Specifically, the mol ratio of SiO2/Al2O3 of the framework of the modified Y molecular sieve is 5.0-6.0, the specific surface area of micropores is 400-600 m2/g, the pore volume of micropores is 0.25-0.35 cm3/g, the specific surface area of mesopores is 30-200 m2/g, the pore volume of mesopores is 0.07-0.85 cm3/g, the pore diameter of mesopores is 2.0-6.0 nm, and the content of sodium oxide in the modified Y molecular sieve is not more than 0.1 wt% based on the total weight of the modified Y molecular sieve.

According to the present disclosure, in order to further improve the catalytic performance of the catalyst, the catalyst may include 59 to 85 wt% of the modified Y molecular sieve based on the dry weight of the catalyst, 14 to 40 wt% of the carrier based on the dry weight of the catalyst, and 0.1 to 1 wt% of the metal promoter having a hydrogenation function based on the metal. Compared with the existing solid acid alkylation catalyst, the catalyst disclosed by the invention has higher molecular sieve content, higher strength and longer service life, and the strength of the catalyst can be 8-9.3N/mm.

According to the present disclosure, the modified Y molecular sieve may be prepared by a method comprising the steps of:

b. Mixing the second mixture obtained in the step a with water, a silicon source and an aluminum source to obtain a third mixture;

c. b, performing hydrothermal crystallization on the third mixture obtained in the step b, and collecting a solid obtained after the hydrothermal crystallization;

The method comprises the steps of firstly preparing a directing agent by adopting a special treatment means, and then carrying out hydrothermal crystallization on a mixture consisting of the directing agent, water, a silicon source and an aluminum source to obtain a crystallized product containing small crystal grains NaY. Filtering out crystallization mother liquor, pulping again, assembling the small crystal grain NaY by using amorphous silica-alumina remained in the obtained slurry and remained on the surface of the small crystal grain NaY under the action of an organosilane coupling agent and a surfactant to obtain the NaY molecular sieve with a regular mesoporous-microporous structure stacked by the small crystal grain NaY. The average grain size of the small-grain NaY can be adjusted between 50-200 nm, 200-500 nm and 500-800 nm. And finally, carrying out ammonium sodium reduction, hydrothermal treatment and post-treatment modification of dealuminization and silicon supplementation on the NaY molecular sieve with regular mesopores and micropores to obtain the modified Y molecular sieve.

According to the disclosure, in the step a, the mixing of sodium metaaluminate and water glass may be performed at a temperature of 15 to 60 ℃ under stirring, and the composition of the first mixture may be Na2O: A12O3: SiO2 ═ 6 to 25: 1: (6-25).

According to the disclosure, in step a, the first mixture is subjected to dynamic aging, standing aging and water addition in sequence to obtain the second mixture. The dynamic aging may include: stirring and aging for 5-48 hours at 15-60 ℃; the standing aging may include: standing and aging for 5-48 hours at 15-60 ℃. After dynamic and aging standing and aging, water can be added under the stirring condition until the required proportion of the second mixture is reached, and the obtained second mixture is the guiding agent. The preparation of the guiding agent is different from the conventional preparation process of the NaY molecular sieve guiding agent in which a silicon source and an aluminum source are mixed in any order and are aged under a static condition after being uniformly mixed, and the guiding agent prepared by the process is adopted to carry out subsequent hydrothermal crystallization, so that a crystallized product containing small-grain NaY can be obtained more favorably.

In step b, the second mixture, water, the silicon source, and the aluminum source may be mixed in a variety of feeding sequences according to the present disclosure. For example, water can be added first, a silicon source and an aluminum source are added simultaneously under rapid stirring, and a directing agent is added after uniform stirring; or the materials are fed in sequence according to the sequence of water, an aluminum source, a silicon source and a guiding agent under the rapid stirring; or feeding the materials according to the sequence of water, a silicon source, an aluminum source and a guiding agent under rapid stirring; or feeding the silicon source, the water, the guiding agent and the aluminum source in sequence under rapid stirring; preferably, the third mixture is obtained by sequentially adding the directing agent, the silicon source, the aluminum source and the water to a mixing tank. The composition of the third mixture, calculated as oxides and in moles, may be Na2O: A12O3: SiO2: H2O ═ 2-6: 1: (8-20): (200-400). The aluminum element in the second mixture may account for 3 to 30% of the aluminum element in the third mixture by element and by mole.

According to the present disclosure, in step b, the water may be deionized water or distilled water. The silicon source may be an inorganic silicon source commonly used for synthesizing NaY molecular sieve, for example, at least one selected from water glass, silica sol, silica gel and silica white. The aluminum source may also be conventional for synthesizing NaY molecular sieves, such as at least one selected from the group consisting of sodium metaaluminate, aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum hydroxide, and pseudoboehmite.

According to the present disclosure, in step c, the conditions of the hydrothermal crystallization may be conventional conditions for synthesizing NaY molecular sieve, such as: the temperature can be 90-100 ℃ and the time can be 15-48 hours.

According to the disclosure, slurry containing small crystal grain NaY can be obtained after hydrothermal crystallization, then crystallization mother liquor is filtered, solid obtained after hydrothermal crystallization is collected, the solid is pulped again, silane coupling agent and surfactant are added, assembly reaction can occur, and the regular mesoporous-microporous NaY molecular sieve formed by stacking small crystal grain NaY is obtained. In step d, the molar ratio of the slurry to the silane coupling agent and the surfactant in terms of a12O3 may be 1: (0.04-10): (0.04-10). The meaning of reslurrying is well known to those skilled in the art and means that the solid from which the crystallization mother liquor is filtered is added to water and optional solvent and stirred uniformly, the amount of the added water and optional solvent can vary widely, and the disclosure is not particularly limited.

In step d, as is well known to those skilled in the art, the silane coupling agent may be a compound represented by the general formula R1Si (L1)3, wherein L1 may be one selected from methoxy, ethoxy, chlorine and methoxyethoxy, R1 may be one selected from phenyl, C1 to C22 chain alkyl, C1 to C22 alkenyl and hydrocarbon group having a substituent at the end, and the substituent may be at least one selected from chlorine, amino, epoxy, vinyl and methacryloxy. Further, the silane coupling agent may be at least one selected from the group consisting of octadecyltrimethoxysilane, vinyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane and 3- (2, 3-glycidoxy) propyltrimethoxysilane.

In step d, the quaternary ammonium salt surfactant is well known to those skilled in the art, and may be a compound represented by the general formula R2N (R3)3X, wherein R2 may be a C8 to C22 chain alkyl group, R3 may be a hydrocarbon group, and X is a halogen (e.g., Cl or Br) or a hydroxyl group. Further, the surfactant may be at least one selected from the group consisting of dodecyltrimethylammonium bromide (C15H28NBr), tetradecyltrimethylammonium bromide (C17H32NBr), and hexadecyltrimethylammonium bromide (C19H36 NBr).

According to the disclosure, after the NaY molecular sieve with the regular mesoporous-microporous structure, which is formed by stacking small crystal grains NaY, is obtained, ammonium sodium exchange reduction, hydrothermal treatment and dealumination and silicon supplement are performed on the NaY molecular sieve, so that the modified Y molecular sieve can be obtained.

in step e, the ammonium crosslinked sodium is well known to those skilled in the art, and the purpose of the ammonium crosslinked sodium is to reduce the content of sodium oxide in the molecular sieve to 2.5-5.0 wt%. Specifically, the ammonium croscarmellose sodium may include: and treating the NaY molecular sieve by adopting an ammonium salt solution with the ammonium ion concentration of 0.1-1.0 mol/L. The conditions of the treatment may be: the temperature is 50-100 ℃, and the liquid-solid weight ratio is (8-15): 1 for 0.5 to 1.5 hours, and the treatment can be carried out under stirring conditions. The ammonium salt may be at least one selected from ammonium nitrate, ammonium sulfate, ammonium chloride and ammonium acetate. The ammonium-sodium reduction process can be carried out once or more times until the content of sodium oxide in the NaY molecular sieve is reduced to a target value.

The hydrothermal treatment and dealumination and silicon supplementation in step e are also well known to those skilled in the art in light of the present disclosure. Specifically, the hydrothermal treatment may include: treating the NaY molecular sieve subjected to sodium reduction by ammonium exchange for 1-3 hours under the conditions of 100% of water vapor, gauge pressure of 0.1-0.2 MPa and temperature of 500-650 ℃. The dealuminizing and silicon supplementing may include: pulping the NaY molecular sieve after the hydrothermal treatment to obtain a product with a liquid-solid weight ratio of (3-10): 1, (NH4)2SiF6 is added into the slurry according to the charging amount of 10-60 g (NH4)2SiF6 added into each 100g of NaY molecular sieve, and the mixture is stirred for 0.5-5 hours at the temperature of 80-120 ℃, so that a product is recovered. The process of recovering the product may include filtration and drying. Through hydrothermal treatment and dealumination and silicon supplement, silicon in ammonium hexafluorosilicate is mainly supplemented to the surface of the NaY molecular sieve, crystal lattice vacancies generated by removing silicon and aluminum during hydrothermal aging are filled, the surface silicon-aluminum ratio of the NaY molecular sieve is greatly increased, the integral framework silicon-aluminum ratio is only slightly increased, and finally the obtained modified Y molecular sieve unit cell has only slight shrinkage.

In accordance with the present disclosure, the support may include a first component comprising alumina, a second component comprising silica, and optionally clay. Further, the weight ratio of the first component, calculated as Al2O3, the second component, calculated as SiO2, and the clay, calculated on a dry basis, may be 1: (0.01-1): (0-3). Further, the first component may include an alumina sol and hydrated alumina, which may be, for example, hydrated alumina having a pseudo-Boehmite structure (pseudoboehmite), a Boehmite structure (Boehmite), a Gibbsite structure (Gibbsite), and a bayer structure (bayer), preferably pseudo-Boehmite and Gibbsite; the weight ratio of the aluminum sol to the hydrated alumina, calculated as Al2O3, may be 1: (0.2-5). The second component may be at least one selected from the group consisting of silica sol, orthosilicate (e.g., methyl orthosilicate, ethyl orthosilicate, etc.), and silica. The clay is not particularly limited, and examples thereof include kaolin, bentonite, and activated clay.

According to the disclosure, the metal promoter having a hydrogenation function may be at least one selected from group viii metals, preferably at least one selected from group viii noble metals. Further preferably, the metal auxiliary agent having a hydrogenation function may be at least one selected from rhodium, platinum, palladium, nickel and ruthenium.

The specific surface area of the micropores of the solid acid alkylation catalyst provided by the disclosure can be 300-600 m2/g, the pore volume of the micropores can be 0.15-0.30 cm3/g, the specific surface area of the mesopores can be 110-200 m2/g, the pore volume of the mesopores can be 0.20-0.85 cm3/g, and the pore size of the mesopores can be 2.0-6.0 nm.

In a second aspect of the present disclosure: there is provided a process for preparing a catalyst according to the first aspect of the present disclosure. In one embodiment of the present disclosure, the method may include:

And forming and roasting the mixed slurry containing the modified Y molecular sieve, the carrier and the adhesion promoter to obtain a roasted material, and then loading the metal auxiliary agent with the hydrogenation function on the roasted material to obtain the solid acid alkylation catalyst.

Alternatively, in another embodiment of the present disclosure, the method may comprise:

In both of the above embodiments, the adhesion promoter is conventionally used for molding, and may include, for example, an acid, which may be at least one selected from hydrochloric acid, nitric acid, and phosphoric acid, and water. The solid content of the mixed slurry may be 35 to 40% by weight. The molding may be at least one selected from the group consisting of bar extrusion molding, ball rolling molding, and spray molding.

In a preferred embodiment of the present disclosure, in order to prepare a spherical catalyst for catalyzing an alkylation reaction, the carrier includes hydrated alumina, alumina sol, silica sol and clay, and the sequential order of adding the components during molding may be: adding acid into hydrated alumina, adding clay, mixing, adding modified Y molecular sieve (or metal-loaded Y molecular sieve), and adding aluminum sol, silica sol and water. Further, the modified Y molecular sieve (or metal-loaded Y molecular sieve) may be suitably pre-kneaded with a mixture of hydrated alumina, alumina sol, silica sol, clay and acid prior to the addition of water. The material after adding water can be kneaded for 30-40 min. Kneading time directly affects the subsequent forming (extrusion and ball forming). The kneading is insufficient, the material is difficult to extrude, the extruded strips have more burrs, multiple white spots and easy breakage, and balls with undersized particle size tend to be generated during rolling; too long a kneading time may damage the pore structure and specific surface of the support. The control of water addition is particularly important, and is the most critical factor for the smoothness of subsequent rolling balls, and the over-dry and over-wet materials can not be extruded into strips and rolling balls. In order to avoid excessive water addition, the humidity of the materials is observed in the mixing and kneading process at proper time, when the water addition amount is proper, partial lumps of the materials appear after 20min of mixing and kneading, and the kneaded bulk materials can be agglomerated but are not sticky and can be scattered after loosening. No lumps are present or a moisture content in the wet base of 35-40% is suitable. The bar extruding step is also a key step, and the operability of subsequent rolling balls can be well predicted according to the condition of the extruded bar, so that the best condition for the rolling balls can be created as far as possible during bar extruding. The ideal state for extruded strands is: continuous discharging, smooth surface, high toughness and no curling and stickiness. The speed of extruding the strips is controlled well in the process of extruding the strips, the speed of extruding the strips and the speed of rolling balls are balanced as much as possible, and excessive extruding of the strips is avoided. The rolling ball is the last key step of the forming, and directly influences the primary yield, the particle size distribution, the roundness and the like of the catalyst pellets. In the process of rolling the ball, careful operation is carried out, and proper parameters are selected, so that the generation probability of the small ball and the strip-shaped object can be reduced. The means for regulating and controlling the rolling ball include rotating speed, blowing quantity, feeding quantity and rolling time. The balling condition should be monitored in good time during the balling process, and the operating parameters should be adjusted in time to ensure that the balling is carried out under the optimal condition. For example, the parameter conditions may be: the rotating speed is 25 to 45r/min, the rolling time is 0.5 to 2h, and the like.

According to the present disclosure, the manner of supporting the metal promoter with hydrogenation function may be well known to those skilled in the art, for example, equivalent volume impregnation and/or ion exchange may be adopted, and the specific operation steps of the above embodiment are well described in the prior art, and are not repeated in the present disclosure. After the metal auxiliary agent with the hydrogenation function is loaded, the steps of drying and roasting can also be carried out, the steps are conventional steps for preparing the catalyst, and the disclosure is not particularly limited.

According to the present disclosure, the firing conditions after forming may be: the temperature is 400-600 ℃; the time is 0.5 to 4 hours.

The catalyst provided by the disclosure is particularly suitable for catalyzing the alkylation reaction of isoparaffin and low-carbon olefin. Accordingly, the third aspect of the present disclosure: there is provided a use of the catalyst according to the first aspect of the present disclosure in catalyzing an alkylation reaction of isoparaffin with lower olefin, wherein the alkylation reaction conditions include: the temperature is 40-100 ℃, the pressure is 2.0-5.0 MPa, the feeding space velocity is 10-3000 mL/(g.h), and the molar ratio of the isoparaffin to the low-carbon olefin is (20-1000): 1. further, the isoparaffin can be isoparaffin of C4-C6, preferably isobutane; the low-carbon olefin can be C3-C6 monoolefin, and 1-butene and/or 2-butene is preferred.

In accordance with the present disclosure, the alkylation reaction may be carried out in conventional various forms of reactors, including fluidized bed reactors, slurry bed reactors, and fixed bed reactors, and may be carried out in a single or multiple reactors.

the catalyst disclosed by the invention can be used for catalyzing isoparaffin and low-carbon olefin, so that the selectivity of a target product trimethylpentane can be effectively improved, the yield of an unnecessary C9+ byproduct can be limited, the service life of the catalyst is long, the stability is good, and the activity can be restored to the level of a fresh agent after the catalyst is regenerated by hydrogen.

The present disclosure is further illustrated below by reference to examples and comparative examples, but the scope of the present disclosure is not limited thereto.

in each of the examples and comparative examples, the molecular sieve crystal structure was determined by X-ray powder diffractometry (XRD) using Holand PANalytical X' Pert PRO MPD type with Cu Ka radiation at an operating voltage of 40kV and a current of 40 mA. The calculation method of the relative crystallinity and the crystal retention degree comprises the following steps: the crystallinity of the standard sample was defined as 100%, and relative crystallinity was obtained by comparing characteristic peaks of XRD at 15.6 °, 18.6 °, 20.3 °, 23.4 °, 27.0 °, 30.7 °, 31.3 ° and 34.0 ° at 2 θ of the synthesized sample with the characteristic peaks of the standard sample. The grain size of the molecular sieve is determined by a Scanning Electron Microscope (SEM) and observed by a JSM-5610LV type scanning electron microscope.

The BET adsorption-desorption isotherms and pore distributions of the molecular sieve catalyst samples were determined by static low temperature nitrogen adsorption volumetric method (BET). The experimental apparatus used was an ASAP-2405 static nitrogen adsorption apparatus from Micromeritics, USA. The process is as follows: liquid nitrogen is contacted with the adsorbent at 77K, and the adsorbent is kept still to reach adsorption equilibrium. And calculating the amount of nitrogen adsorbed by the adsorbent according to the difference between the nitrogen gas inflow and the gas amount remained in the gas phase after adsorption. The specific surface area of micropores and the specific surface area of mesopores are calculated by using a two-parameter BET formula, and the pore size distribution is calculated by using a BJH formula.

The morphology of the molecular sieve is observed by an electron microscope. The sample is plated with a layer of gold before testing, wherein the sample is a Scanning Electron Microscope (SEM) instrument model Hitachi S-4300, the accelerating voltage is 10kV, an accessory is provided with an Energy Dispersive Spectroscopy (EDS). Observing the catalyst by using a FEI Tecnai G2F20 field emission transmission electron microscope, adopting a suspension method to prepare a sample, dispersing the catalyst sample by using absolute ethyl alcohol, uniformly shaking, dripping the mixture onto a copper net, and observing after the ethyl alcohol is completely volatilized.

The strength of the catalyst is measured by an ZQJ-II type intelligent particle strength tester (produced by Dalian intelligent tester), the particle diameter is less than 30mm, and the resolution is 0.1N.

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solid acid alkylation catalyst and preparation method and application thereof

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